Prostaglandin F2alpha (PGF2alpha) is formed in a variety of cells from PGH2, which itself is synthesized from arachidonic acid by the enzyme prostaglandin synthetase. PGF2alpha is often viewed as an antagonist to PGE2 due to their opposing effects on various tissues. PGF2alpha is a potent bronchoconstrictor and has been implicated in asthma attacks. PGF2alpha is also involved in reproductive functions including corpus luteum regulation, uterine contractions, and sperm motility. This has led to its use in terminating pregnancies and inducing labor at term. High levels of PGF2alpha have also been associated with preeclampsia.